Systems and methods for real time drilling fluid management

ABSTRACT

Disclosed are systems and methods for monitoring drilling fluid components in real time. One system includes solids control equipment fluidly coupled to a borehole and configured to receive drilling fluid from the borehole, the solids control equipment having a first optical computing device arranged adjacent the inlet and configured to optically interact with the drilling fluid as it enters the solids control equipment and thereby generate a first output signal corresponding to a characteristic of the drilling fluid, a second optical computing device arranged adjacent the outlet and configured to optically interact with the drilling fluid as it exits the solids control equipment and thereby generate a second output signal corresponding to the characteristic of the drilling fluid, and a signal processor communicably coupled to the first and second optical computing devices and configured to receive the first and second output signals and provide a resulting output signal.

BACKGROUND

The present invention relates to methods for monitoring drilling fluidsand, more specifically, to methods for monitoring drilling fluidcomponents in real time.

During the drilling of a hydrocarbon-producing well, a drilling fluid ormud is continuously circulated from the surface down to the bottom ofthe hole being drilled and back to the surface again. The drilling fluidserves several functions, one of them being to transport wellborecuttings up to the surface where they are separated from the drillingfluid. Another function of the drilling fluid is to provide hydrostaticpressure on the walls of the drilled borehole so as to prevent wellborecollapse and the resulting influx of gas or liquid from the formationsbeing drilled. For several reasons, it can be important to preciselyknow the characteristics and chemical composition of such drillingfluids.

Typically, the analysis of drilling fluids has been conducted off-lineusing laboratory analyses which require the extraction of a sample ofthe fluid and a subsequent controlled testing procedure usuallyconducted at a separate location. Depending on the analysis required,however, such an approach can take hours to days to complete, and evenin the best case scenario, a job will often be completed prior to theanalysis being obtained. Although off-line, retrospective analyses canbe satisfactory in certain cases, but they nonetheless do not allowreal-time or near real-time analysis capabilities. As a result,proactive control of drilling operations cannot take place, at leastwithout significant process disruption occurring while awaiting theresults of the analysis. Off-line, retrospective analyses can also beunsatisfactory for determining true characteristics of a drilling fluidsince the characteristics of the extracted sample of the drilling fluidoftentimes changes during the lag time between collection and analysis,thereby making the properties of the sample non-indicative of the truechemical composition or characteristic.

Monitoring drilling fluids in real-time can be of considerable interestin order to determine how the drilling fluid changes over time, therebyserving as a quality control measure that may be useful in drillingfluid maintenance and drilling optimization. For instance, the viscosityof the drilling fluid is an important characteristic to monitor since itcontributes to the capability of the drilling fluid to adequatelytransport cuttings. Clays, such as bentonite clay, are often added tothe drilling fluid so as to maintain the drilled cuttings suspendedwithin the drilling fluid as they move up the borehole. The density ofthe drilling fluid is another significant characteristic to monitor. Thedensity must exhibit a certain hydrostatic pressure on the formation inorder to avoid wellbore collapse, but not too large such that it wouldfracture the formation. Weighting materials, such as barite, are oftenadded to the drilling fluid to make it exert as much pressure as neededto contain the formation pressures. Several other chemicals orsubstances may be added to the drilling fluid to give the drilling fluidthe exact properties it needs to make it as easy as possible to drillthe wellbore.

In order to optimize the performance of a drilling fluid during drillingoperations, the physical and chemical properties of the drilling fluidand its component parts must be carefully monitored and controlled. Assuch, there is a continued and ongoing need for improved methods andsystems that provide real time monitoring of drilling fluids.

SUMMARY OF THE INVENTION

The present invention relates to methods for monitoring drilling fluidsand, more specifically, to methods for monitoring drilling fluidcomponents in real time.

In some embodiments, a system is disclosed that may include solidscontrol equipment fluidly coupled to a borehole and configured toreceive drilling fluid from the borehole, the solids control equipmenthaving an inlet and an outlet, a first optical computing device arrangedadjacent the inlet and having a first integrated computational elementconfigured to optically interact with the drilling fluid as it entersthe solids control equipment and thereby generate a first output signalcorresponding to a characteristic of the drilling fluid, a secondoptical computing device arranged adjacent the outlet and having asecond integrated computational element configured to optically interactwith the drilling fluid as it exits the solids control equipment andthereby generate a second output signal corresponding to thecharacteristic of the drilling fluid, and a signal processorcommunicably coupled to the first and second optical computing devicesand configured to receive the first and second output signals andprovide a resulting output signal.

In other embodiments, a method of determining a characteristic of adrilling fluid is disclosed. The method may include conveying thedrilling fluid to solids control equipment fluidly coupled to aborehole, the solids control equipment having an inlet and an outlet,generating a first output signal corresponding to the characteristic ofthe drilling fluid with a first optical computing device arrangedadjacent the inlet, the first optical computing device having a firstintegrated computational element configured to optically interact withthe drilling fluid as it enters the solids control equipment, generatinga second output signal corresponding to the characteristic of thedrilling fluid with a second optical computing device arranged adjacentthe outlet, the second optical computing device having a secondintegrated computational element configured to optically interact withthe drilling fluid as it exits the solids control equipment, receivingthe first and second output signals with a signal processor communicablycoupled to the first and second optical computing devices, andgenerating a resulting output signal with the signal processor.

In yet other embodiments, a system is disclosed that may include solidscontrol equipment fluidly coupled to a borehole and configured toreceive drilling fluid from the borehole, the solids control equipmenthaving an inlet and an outlet, an optical computing device arrangedadjacent the outlet and having an integrated computational elementconfigured to optically interact with the drilling fluid as it exits thesolids control equipment and generate an output signal corresponding toa characteristic of the drilling fluid, and a signal processorcommunicably coupled to the optical computing device and configured toreceive the output signal and provide a resulting output signalindicative of the characteristic of the drilling fluid.

The features and advantages of the present invention will be readilyapparent to those skilled in the art upon a reading of the descriptionof the preferred embodiments that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of thepresent invention, and should not be viewed as exclusive embodiments.The subject matter disclosed is capable of considerable modifications,alterations, combinations, and equivalents in form and function, as willoccur to those skilled in the art and having the benefit of thisdisclosure.

FIG. 1 illustrates an exemplary integrated computation element,according to one or more embodiments.

FIG. 2 illustrates an exemplary optical computing device for monitoringa fluid, according to one or more embodiments.

FIG. 3 illustrates another exemplary optical computing device formonitoring a fluid, according to one or more embodiments.

FIG. 4 illustrates an exemplary wellbore drilling assembly that mayemploy one or more optical computing devices for monitoring a fluid,according to one or more embodiments.

DETAILED DESCRIPTION

The present invention relates to methods for monitoring drilling fluidsand, more specifically, to methods for monitoring drilling fluidcomponents in real time.

The exemplary systems and methods described herein employ variousconfigurations of optical computing devices, also commonly referred toas “opticoanalytical devices,” for the real-time or near real-timemonitoring of a fluid, such as a drilling fluid or a completion fluid.In operation, the exemplary systems and methods may be useful andotherwise advantageous in determining one or more properties orcharacteristics of the fluid, such as a concentration of one or morecomponents or substances present within the fluid. The optical computingdevices, which are described in more detail below, can advantageouslyprovide real-time fluid monitoring that cannot presently be achievedwith either onsite analyses at a job site or via more detailed analysesthat take place in a laboratory. A significant and distinct advantage ofthese devices is that they can be configured to specifically detectand/or measure a particular component or characteristic of interest of afluid, thereby allowing qualitative and/or quantitative analyses of thefluid to occur without having to extract a sample and undertaketime-consuming analyses of the sample at an off-site laboratory. Withthe ability to undertake real-time or near real-time analyses, theexemplary systems and methods described herein may be able to providesome measure of proactive or responsive control over the fluid flow,thereby optimizing related operations.

The systems and methods disclosed herein may be suitable for use in theoil and gas industry since the described optical computing devicesprovide a cost-effective, rugged, and accurate means for monitoringoil/gas-related fluids, such as drilling fluids or completion fluids, inorder to facilitate the efficient management of wellbore operations. Theoptical computing devices can be deployed various points within a flowpath to monitor the fluid and the various parameter changes that mayoccur thereto. Depending on the location of the particular opticalcomputing device, different types of information about the fluid can beobtained. In some cases, for example, the optical computing devices canbe used to monitor changes to the fluid following circulation of thefluid into and out of a wellbore. In other embodiments, the opticalcomputing devices can be used to monitor the fluid as a result of addinga component or substance thereto, or otherwise removing a component orsubstance therefrom. In yet other embodiments, the concentration ofknown constituent components present within the fluid may be monitored.Thus, the systems and methods described herein may be configured tomonitor a flow of fluids and, more particularly, to monitor the presentstate of the fluid and any changes thereto with respect to anyconstituent components present therein.

As used herein, the term “fluid” refers to any substance that is capableof flowing, including particulate solids, liquids, gases, slurries,emulsions, powders, muds, mixtures, combinations thereof, and the like.In some embodiments, the fluid may be a drilling fluid or drilling mud,including water-based drilling fluids, oil-based drilling fluids,synthetic drilling fluids, and the like. In other embodiments, the fluidmay be a completion fluid or clean-up fluid such as, but not limited to,fresh water, saltwater (e.g., water containing one or more saltsdissolved therein), brine (e.g., saturated salt water, chloride salts,bromide salts, combinations thereof, etc.), seawater, a spacer fluid,base fluids, or other treatment fluids known in the art.

As used herein, the term “characteristic” refers to a chemical,mechanical, or physical property of a component or a substance, such asa fluid, or a component within the fluid. A characteristic of asubstance may include a quantitative value of one or more chemicalconstituents therein or physical properties associated therewith. Suchchemical constituents may be referred to herein as “analytes.”Illustrative characteristics of a substance that can be monitored withthe optical computing devices disclosed herein can include, for example,chemical composition (e.g., identity and concentration in total or ofindividual components), phase presence (e.g., gas, oil, water, etc.),impurity content, pH, alkalinity, viscosity, density, ionic strength,total dissolved solids, salt content (e.g., salinity), porosity,opacity, bacteria content, total hardness, combinations thereof, stateof matter (solid, liquid, gas, emulsion, mixtures, etc), and the like.Moreover, the phrase “characteristic of interest of/in a fluid” may beused herein to refer to the characteristic of a substance contained inor otherwise flowing with the fluid.

As used herein, the term “flow path” refers to a route through which afluid is capable of being transported between at least two points. Insome cases, the flow path need not be continuous or otherwise contiguousbetween the two points. Exemplary flow paths include, but are notlimited to, a flow line, a pipeline, production tubing, drill string,work string, casing, a wellbore, an annulus defined between a wellboreand any tubular arranged within the wellbore, a mud pit, a subterraneanformation, etc., combinations thereof, or the like. It should be notedthat the term “flow path” does not necessarily imply that a fluid isflowing therein, rather that a fluid is capable of being transported orotherwise flowable therethrough.

As used herein, the term “component,” or variations thereof, refers toat least a portion of a substance or material of interest in the fluidto be evaluated using the optical computing devices described herein. Insome embodiments, the component is the characteristic of interest, asdefined above, and may include any integral constituent of the fluidflowing within the flow path. For example, the component may includecompounds containing elements such as barium, calcium (e.g., calciumcarbonate), carbon (e.g., graphitic resilient carbon), chlorine (e.g.,chlorides), manganese, sulfur, iron, strontium, chlorine, etc., and anychemical substance that may lead to precipitation within a flow path.The component may also refer to paraffins, waxes, asphaltenes, clays(e.g., smectite, illite, kaolins, etc.), aromatics, saturates, foams,salts, particulates, hydrates, sand or other solid particles (e.g., lowand high gravity solids), combinations thereof, and the like. In yetother embodiments, in terms of quantifying ionic strength, the componentmay include various ions, such as, but not limited to, Ba₂ ⁺, Sr₂ ⁺,Fe⁺, Fe₂ ⁺ (or total Fe), Mn₂ ⁺, SO₄ ²⁻, CO₃ ²⁻, Ca₂ ⁺, Mg₂ ⁺, Na⁺, K⁺,Cl⁻.

In other aspects, the component may refer to any substance or materialadded to the fluid as an additive or in order to treat the fluid or theflow path. For instance, the component may include, but is not limitedto, acids, acid-generating compounds, bases, base-generating compounds,biocides, surfactants, scale inhibitors, corrosion inhibitors, gellingagents, crosslinking agents, anti-sludging agents, foaming agents,defoaming agents, antifoam agents, emulsifying agents and emulsifiers,de-emulsifying agents, iron control agents, proppants or otherparticulates, gravel, particulate diverters, salts, fluid loss controladditives, gases, catalysts, clay control agents, clay stabilizers, clayinhibitors, chelating agents, corrosion inhibitors, dispersants,flocculants, base fluids (e.g., water, brines, oils), scavengers (e.g.,H₂S scavengers, CO₂ scavengers or O₂ scavengers), lubricants, breakers,delayed release breakers, friction reducers, bridging agents,viscosifiers, thinners, high-heat polymers, tar treatments, weightingagents or materials (e.g., barite, etc.), solubilizers, rheology controlagents, viscosity modifiers, pH control agents (e.g., buffers), hydrateinhibitors, relative permeability modifiers, diverting agents,consolidating agents, fibrous materials, bactericides, tracers, probes,nanoparticles, and the like. Combinations of these substances can bereferred to as a substance as well.

As used herein, the term “electromagnetic radiation” refers to radiowaves, microwave radiation, infrared and near-infrared radiation,visible light, ultraviolet light, X-ray radiation and gamma rayradiation.

As used herein, the term “optical computing device” refers to an opticaldevice that is configured to receive an input of electromagneticradiation associated with a fluid and produce an output ofelectromagnetic radiation from a processing element arranged within theoptical computing device. The processing element may be, for example, anintegrated computational element (ICE), also known as a multivariateoptical element (MOE), used in the optical computing device. Theelectromagnetic radiation that optically interacts with the processingelement is changed so as to be readable by a detector, such that anoutput of the detector can be correlated to a characteristic of thefluid or a component present within the fluid. The output ofelectromagnetic radiation from the processing element can be reflectedelectromagnetic radiation, transmitted electromagnetic radiation, and/ordispersed electromagnetic radiation. Whether the detector analyzesreflected, transmitted, or dispersed electromagnetic radiation may bedictated by the structural parameters of the optical computing device aswell as other considerations known to those skilled in the art. Inaddition, emission and/or scattering of the fluid, for example viafluorescence, luminescence, Raman, Mie, and/or Raleigh scattering, canalso be monitored by the optical computing devices.

As used herein, the term “optically interact” or variations thereofrefers to the reflection, transmission, scattering, diffraction, orabsorption of electromagnetic radiation either on, through, or from oneor more processing elements (i.e., integrated computational elements ormultivariate optical elements), a fluid, or a component present withinthe fluid. Accordingly, optically interacted light refers toelectromagnetic radiation that has been reflected, transmitted,scattered, diffracted, or absorbed by, emitted, or re-radiated, forexample, using a processing element, but may also apply to interactionwith a fluid or a component of the fluid.

The exemplary systems and methods described herein will include at leastone optical computing device arranged along or in a flow path in orderto monitor a fluid contained therein. Each optical computing device mayinclude an electromagnetic radiation source, at least one processingelement (e.g., an integrated computational element), and at least onedetector arranged to receive optically interacted light from the atleast one processing element or the fluid. As disclosed below, however,in at least one embodiment, the electromagnetic radiation source may beomitted and instead the electromagnetic radiation may be derived fromthe fluid itself. In some embodiments, the exemplary optical computingdevices may be specifically configured for detecting, analyzing, andquantitatively measuring a particular characteristic of the fluid or acomponent present within the fluid. In other embodiments, the opticalcomputing devices may be general purpose optical devices, withpost-acquisition processing (e.g., through computer means) being used tospecifically detect the characteristic of the sample.

In some embodiments, suitable structural components for the exemplaryoptical computing devices are described in commonly owned U.S. Pat. Nos.6,198,531; 6,529,276; 7,123,844; 7,834,999; 7,911,605, 7,920,258, and8,049,881, each of which is incorporated herein by reference in itsentirety, and U.S. patent application Ser. Nos. 12/094,460; 12/094,465;and 13/456,467, each of which is also incorporated herein by referencein its entirety. The optical computing devices described in theforegoing patents and patent applications can perform calculations(analyses) in real-time or near real-time without the need fortime-consuming sample processing. Moreover, the optical computingdevices can be specifically configured to detect and analyze particularcharacteristics of a fluid or a component present within the fluid. As aresult, interfering signals are discriminated from those of interest inthe fluid by appropriate configuration of the optical computing devices,such that the optical computing devices provide a rapid responseregarding the characteristics of the fluid as based on the detectedoutput. In some embodiments, the detected output can be converted into avoltage that is distinctive of the magnitude of the characteristic ofthe fluid or a component present therein.

The optical computing devices can be configured to detect not only thecomposition and concentrations of a fluid or a component therein, butthey also can be configured to determine physical properties and othercharacteristics of the fluid and/or component as well, based on ananalysis of the electromagnetic radiation received from the fluid and/orcomponent. For example, the optical computing devices can be configuredto determine the concentration of an analyte and correlate thedetermined concentration to a characteristic of the fluid or componentby using suitable processing means. As will be appreciated, the opticalcomputing devices may be configured to detect as many characteristics ofthe fluid or component as desired. All that is required to accomplishthe monitoring of multiple characteristics is the incorporation ofsuitable processing and detection means within the optical computingdevice for each characteristic. In some embodiments, the properties ofthe fluid or component can be a combination of the properties of theanalytes therein (e.g., a linear, non-linear, logarithmic, and/orexponential combination). Accordingly, the more characteristics andanalytes that are detected and analyzed using the optical computingdevices, the more accurately the properties of the given fluid and/orcomponent will be determined.

The optical computing devices described herein utilize electromagneticradiation to perform calculations, as opposed to the hardwired circuitsof conventional electronic processors. When electromagnetic radiationinteracts with a fluid, unique physical and chemical information aboutthe fluid may be encoded in the electromagnetic radiation that isreflected from, transmitted through, or radiated from the fluid. Thisinformation is often referred to as the spectral “fingerprint” of thefluid. The optical computing devices described herein are capable ofextracting the information of the spectral fingerprint of multiplecharacteristics or analytes within a fluid, and converting thatinformation into a detectable output relating to one or morecharacteristics of the fluid or a component present within the fluid.That is, through suitable configurations of the optical computingdevices, electromagnetic radiation associated with a characteristic oranalyte of interest of a fluid can be separated from electromagneticradiation associated with all other components of the fluid in order toestimate the properties of the fluid in real-time or near real-time.

The processing elements used in the exemplary optical computing devicesdescribed herein may be characterized as integrated computationalelements (ICE). Each ICE is capable of distinguishing electromagneticradiation related to the characteristic of interest from electromagneticradiation related to other components of a fluid. Referring to FIG. 1,illustrated is an exemplary ICE 100 suitable for use in the opticalcomputing devices used in the systems and methods described herein. Asillustrated, the ICE 100 may include a plurality of alternating layers102 and 104, such as silicon (Si) and SiO₂ (quartz), respectively. Ingeneral, these layers 102, 104 consist of materials whose index ofrefraction is high and low, respectively. Other examples might includeniobia and niobium, germanium and germania, MgF, SiO, and other high andlow index materials known in the art. The layers 102, 104 may bestrategically deposited on an optical substrate 106. In someembodiments, the optical substrate 106 is BK-7 optical glass. In otherembodiments, the optical substrate 106 may be another type of opticalsubstrate, such as quartz, sapphire, silicon, germanium, zinc selenide,zinc sulfide, or various plastics such as polycarbonate,polymethylmethacrylate (PMMA), polyvinylchloride (PVC), diamond,ceramics, combinations thereof, and the like.

At the opposite end (e.g., opposite the optical substrate 106 in FIG.1), the ICE 100 may include a layer 108 that is generally exposed to theenvironment of the device or installation. The number of layers 102, 104and the thickness of each layer 102, 104 are determined from thespectral attributes acquired from a spectroscopic analysis of acharacteristic of the fluid using a conventional spectroscopicinstrument. The spectrum of interest of a given characteristic typicallyincludes any number of different wavelengths. It should be understoodthat the exemplary ICE 100 in FIG. 1 does not in fact represent anyparticular characteristic of a given fluid, but is provided for purposesof illustration only. Consequently, the number of layers 102, 104 andtheir relative thicknesses, as shown in FIG. 1, bear no correlation toany particular characteristic. Nor are the layers 102, 104 and theirrelative thicknesses necessarily drawn to scale, and therefore shouldnot be considered limiting of the present disclosure. Moreover, thoseskilled in the art will readily recognize that the materials that makeup each layer 102, 104 (i.e., Si and SiO₂) may vary, depending on theapplication, cost of materials, and/or applicability of the material tothe given fluid.

In some embodiments, the material of each layer 102, 104 can be doped ortwo or more materials can be combined in a manner to achieve the desiredoptical characteristic. In addition to solids, the exemplary ICE 100 mayalso contain liquids and/or gases, optionally in combination withsolids, in order to produce a desired optical characteristic. In thecase of gases and liquids, the ICE 100 can contain a correspondingvessel (not shown), which houses the gases or liquids. Exemplaryvariations of the ICE 100 may also include holographic optical elements,gratings, piezoelectric, light pipe, digital light pipe (DLP), and/oracousto-optic elements, for example, that can create transmission,reflection, and/or absorptive properties of interest.

The multiple layers 102, 104 exhibit different refractive indices. Byproperly selecting the materials of the layers 102, 104 and theirrelative thickness and spacing, the ICE 100 may be configured toselectively pass/reflect/refract predetermined fractions ofelectromagnetic radiation at different wavelengths. Each wavelength isgiven a predetermined weighting or loading factor. The thickness andspacing of the layers 102, 104 may be determined using a variety ofapproximation methods from the spectrograph of the characteristic oranalyte of interest. These methods may include inverse Fourier transform(IFT) of the optical transmission spectrum and structuring the ICE 100as the physical representation of the IFT. The approximations convertthe IFT into a structure based on known materials with constantrefractive indices. Further information regarding the structures anddesign of exemplary ICE elements (also referred to as multivariateoptical elements) is provided in Applied Optics, Vol. 35, pp. 5484-5492(1996) and Vol. 29, pp. 2876-2893 (1990), which is hereby incorporatedby reference.

The weightings that the layers 102, 104 of the ICE 100 apply at eachwavelength are set to the regression weightings described with respectto a known equation, or data, or spectral signature. Briefly, the ICE100 may be configured to perform the dot product of the input light beaminto the ICE 100 and a desired loaded regression vector represented byeach layer 102, 104 for each wavelength. As a result, the output lightintensity of the ICE 100 is related to the characteristic or analyte ofinterest. Further details regarding how the exemplary ICE 100 is able todistinguish and process electromagnetic radiation related to thecharacteristic or analyte of interest are described in U.S. Pat. Nos.6,198,531; 6,529,276; and 7,920,258, previously incorporated herein byreference.

Referring now to FIG. 2, illustrated is an exemplary optical computingdevice 200 for monitoring a fluid 202, according to one or moreembodiments. In the illustrated embodiment, the fluid 202 may becontained or otherwise flowing within an exemplary flow path 204. Theflow path 204 may be a flow line, a pipeline, a wellbore, an annulusdefined within a wellbore, or any flow lines or pipelines extendingto/from a wellbore. The fluid 202 present within the flow path 204 maybe flowing in the general direction indicated by the arrows A (i.e.,from upstream to downstream). As will be appreciated, however, the flowpath 204 may be any other type of flow path, as generally described orotherwise defined herein. For example, the flow path 204 may be a mudpit (i.e., used for drilling fluids and the like) or any othercontainment or storage vessel, and the fluid 202 may not necessarily beflowing in the direction A while the fluid 202 is being monitored. Assuch, portions of the flow path 204 may be arranged substantiallyvertical, substantially horizontal, or any directional configurationtherebetween, without departing from the scope of the disclosure.

The optical computing device 200 may be configured to determine acharacteristic of interest in the fluid 202 or a component presentwithin the fluid 202. In some embodiments, the device 200 may include anelectromagnetic radiation source 208 configured to emit or otherwisegenerate electromagnetic radiation 210. The electromagnetic radiationsource 208 may be any device capable of emitting or generatingelectromagnetic radiation, as defined herein. For example, theelectromagnetic radiation source 208 may be a light bulb, a lightemitting diode (LED), a laser, a blackbody, a photonic crystal, an X-Raysource, combinations thereof, or the like. In some embodiments, a lens212 may be configured to collect or otherwise receive theelectromagnetic radiation 210 and direct a beam 214 of electromagneticradiation 210 toward the fluid 202. The lens 212 may be any type ofoptical device configured to transmit or otherwise convey theelectromagnetic radiation 210 as desired, such as a normal lens, aFresnel lens, a diffractive optical element, a holographic graphicalelement, a mirror (e.g., a focusing mirror), or a type of collimator. Inother embodiments, the lens 212 may be omitted from the device 200 andthe electromagnetic radiation 210 may instead be directed toward thefluid 202 directly from the electromagnetic radiation source 208.

In one or more embodiments, the device 200 may also include a samplingwindow 216 arranged adjacent to or otherwise in contact with the fluid202 for detection purposes. The sampling window 216 may be made from avariety of transparent, rigid or semi-rigid materials that areconfigured to allow transmission of the electromagnetic radiation 210therethrough. For example, the sampling window 216 may be made of, butis not limited to, glasses, plastics, semi-conductors, crystallinematerials, polycrystalline materials, hot or cold-pressed powders,combinations thereof, or the like. After passing through the samplingwindow 216, the electromagnetic radiation 210 impinges upon andoptically interacts with the fluid 202, including any components presentwithin the fluid 202. As a result, optically interacted radiation 218 isgenerated by and reflected from the fluid 202. Those skilled in the art,however, will readily recognize that alternative variations of thedevice 200 may allow the optically interacted radiation 218 to begenerated by being transmitted, scattered, diffracted, absorbed,emitted, or re-radiated by and/or from the fluid 202, without departingfrom the scope of the disclosure.

The optically interacted radiation 218 generated by the interaction withthe fluid 202 may be directed to or otherwise be received by an ICE 220arranged within the device 200. The ICE 220 may be a spectral componentsubstantially similar to the ICE 100 described above with reference toFIG. 1. Accordingly, in operation the ICE 220 may be configured toreceive the optically interacted radiation 218 and produce modifiedelectromagnetic radiation 222 corresponding to a particularcharacteristic of the fluid 202. In particular, the modifiedelectromagnetic radiation 222 is electromagnetic radiation that hasoptically interacted with the ICE 220, whereby an approximate mimickingof the regression vector corresponding to the characteristic of thefluid 202 is obtained.

While FIG. 2 depicts the ICE 220 as receiving reflected electromagneticradiation from the fluid 202, the ICE 220 may be arranged at any pointalong the optical train of the device 200, without departing from thescope of the disclosure. For example, in one or more embodiments, theICE 220 (as shown in dashed) may be arranged within the optical trainprior to the sampling window 216 and equally obtain substantially thesame results. In other embodiments, the ICE 220 may generate themodified electromagnetic radiation 222 through reflection, instead oftransmission therethrough.

Moreover, while only one ICE 220 is shown in the device 200, embodimentsare contemplated herein which include the use of at least two ICEcomponents in the device 200 configured to cooperatively determine thecharacteristic of interest in the fluid 202. For example, two or moreICE may be arranged in series or parallel within the device 200 andconfigured to receive the optically interacted radiation 218 and therebyenhance sensitivities and detector limits of the device 200. In otherembodiments, two or more ICE may be arranged on a movable assembly, suchas a rotating disc or an oscillating linear array, which moves such thatindividual ICE components are able to be exposed to or otherwiseoptically interact with electromagnetic radiation for a distinct briefperiod of time. The two or more ICE components in any of theseembodiments may be configured to be either associated or disassociatedwith the characteristic of interest in the fluid 202. In otherembodiments, the two or more ICE may be configured to be positively ornegatively correlated with the characteristic of interest in the fluid202. These optional embodiments employing two or more ICE components arefurther described in co-pending U.S. patent application Ser. Nos.13/456,264, 13/456,405, 13/456,302, and 13/456,327, the contents ofwhich are hereby incorporated by reference in their entireties.

In some embodiments, it may be desirable to monitor more than onecharacteristic of interest at a time using the device 200. In suchembodiments, various configurations for multiple ICE components can beused, where each ICE component is configured to detect a particularand/or distinct characteristic of interest. In some embodiments, thecharacteristic can be analyzed sequentially using multiple ICEcomponents that are provided a single beam of electromagnetic radiationbeing reflected from or transmitted through the fluid 202. In someembodiments, multiple ICE components can be arranged on a rotating disc,where the individual ICE components are only exposed to the beam ofelectromagnetic radiation for a short time. Advantages of this approachcan include the ability to analyze multiple characteristics of the fluid202 using a single optical computing device 200 and the opportunity toassay additional characteristics simply by adding additional ICEcomponents to the rotating disc.

In other embodiments, multiple optical computing devices can be placedat a single location along the flow path 204, where each opticalcomputing device contains a unique ICE that is configured to detect aparticular characteristic of interest in the fluid 202. In suchembodiments, a beam splitter can divert a portion of the electromagneticradiation being reflected by, emitted from, or transmitted through thefluid 202 and into each optical computing device. Each optical computingdevice, in turn, can be coupled to a corresponding detector or detectorarray that is configured to detect and analyze an output ofelectromagnetic radiation from the respective optical computing device.Parallel configurations of optical computing devices can be particularlybeneficial for applications that require low power inputs and/or nomoving parts.

Those skilled in the art will appreciate that any of the foregoingconfigurations can further be used in combination with a seriesconfiguration in any of the present embodiments. For example, twooptical computing devices having a rotating disc with a plurality of ICEcomponents arranged thereon can be placed in series for performing ananalysis at a single location along the length of the flow path 204.Likewise, multiple detection stations, each containing optical computingdevices in parallel, can be placed in series for performing a similaranalysis.

The modified electromagnetic radiation 222 generated by the ICE 220 maysubsequently be conveyed to a detector 224 for quantification of thesignal. The detector 224 may be any device capable of detectingelectromagnetic radiation, and may be generally characterized as anoptical transducer. In some embodiments, the detector 224 may be, but isnot limited to, a thermal detector such as a thermopile or photoacousticdetector, a semiconductor detector, a piezo-electric detector, a chargecoupled device (CCD) detector, a video or array detector, a splitdetector, a photon detector (such as a photomultiplier tube),photodiodes, combinations thereof, or the like, or other detectors knownto those skilled in the art.

In some embodiments, the detector 224 may be configured to produce anoutput signal 226 in real-time or near real-time in the form of avoltage (or current) that corresponds to the particular characteristicof interest in the fluid 202. The voltage returned by the detector 224is essentially the dot product of the optical interaction of theoptically interacted radiation 218 with the respective ICE 220 as afunction of the concentration of the characteristic of interest of thefluid 202. As such, the output signal 226 produced by the detector 224and the concentration of the characteristic may be related, for example,directly proportional. In other embodiments, however, the relationshipmay correspond to a polynomial function, an exponential function, alogarithmic function, and/or a combination thereof.

In some embodiments, the device 200 may include a second detector 228,which may be similar to the first detector 224 in that it may be anydevice capable of detecting electromagnetic radiation. The seconddetector 228 may be used to detect radiating deviations stemming fromthe electromagnetic radiation source 208. Undesirable radiatingdeviations can occur in the intensity of the electromagnetic radiation210 due to a wide variety of reasons and potentially causing variousnegative effects on the device 200. These negative effects can beparticularly detrimental for measurements taken over a period of time.In some embodiments, radiating deviations can occur as a result of abuild-up of film or material on the sampling window 216 which has theeffect of reducing the amount and quality of light ultimately reachingthe first detector 224. Without proper compensation, such radiatingdeviations could result in false readings and the output signal 226would no longer be primarily or accurately related to the characteristicof interest.

To compensate for these types of undesirable effects, the seconddetector 228 may be configured to generate a compensating signal 230generally indicative of the radiating deviations of the electromagneticradiation source 208, and thereby normalize the output signal 226generated by the first detector 224. As illustrated, the second detector228 may be configured to receive a portion of the optically interactedradiation 218 via a beamsplitter 232 in order to detect the radiatingdeviations. In other embodiments, however, the second detector 228 maybe arranged to receive electromagnetic radiation from any portion of theoptical train in the device 200 in order to detect the radiatingdeviations, without departing from the scope of the disclosure.

In some applications, the output signal 226 and the compensating signal230 may be conveyed to or otherwise received by a signal processor 234communicably coupled to both the detectors 220, 228. The signalprocessor 234 may be a computer including a processor and amachine-readable storage medium having instructions stored thereon,which, when executed by the processor 234, cause the optical computingdevice 200 to perform a number of operations, such as determining acharacteristic of interest of the fluid 202. For instance, theconcentration of each characteristic detected with the optical computingdevice 200 can be fed into an algorithm operated by the signal processor234. The algorithm can be part of an artificial neural networkconfigured to use the concentration of each detected characteristic inorder to evaluate the overall characteristic(s) or quality of the fluid202. Illustrative but non-limiting artificial neural networks aredescribed in commonly owned U.S. patent application Ser. No. 11/986,763(U.S. Patent App. Pub. No. 2009/0182693), which is incorporated hereinby reference.

The signal processor 234 may also be configured to computationallycombine the compensating signal 230 with the output signal 226 in orderto normalize the output signal 226 in view of any radiating deviationsdetected by the second detector 228. Computationally combining theoutput and compensating signals 220, 228 may entail computing a ratio ofthe two signals 220, 228. For example, the concentration or magnitude ofeach characteristic determined using the optical computing device 200can be fed into an algorithm run by the signal processor 234. Thealgorithm may be configured to make predictions on how thecharacteristics of the fluid 202 change if the concentrations of one ormore components or additives are changed relative to one another.

In real-time or near real-time, the signal processor 234 may beconfigured to provide a resulting output signal 236 corresponding to aconcentration of the characteristic of interest in the fluid 202. Theresulting output signal 236 may be readable by an operator who canconsider the results and make proper adjustments or take appropriateaction, if needed, based upon the measured concentrations of componentsor additives in the fluid 202. In some embodiments, the resulting signaloutput 328 may be conveyed, either wired or wirelessly, to an operatorfor consideration. In other embodiments, the resulting output signal 236may be recognized by the signal processor 234 as being within or withouta predetermined or preprogrammed range of suitable operation and mayalert the operator of an out of range reading so appropriate correctiveaction may be taken, or otherwise autonomously undertake the appropriatecorrective action such that the resulting output signal 236 returns to avalue within the predetermined or preprogrammed range of suitableoperation.

Referring now to FIG. 3, illustrated is another exemplary opticalcomputing device 300 for monitoring the fluid 202, according to one ormore embodiments. The optical computing device 300 may be similar insome respects to the optical computing device 200 of FIG. 2, andtherefore may be best understood with reference thereto where likenumerals indicate like elements that will not be described again. Again,the optical computing device 300 may be configured to determine theconcentration of a characteristic of interest in the fluid 202 ascontained within the flow path 204. Unlike the device 200 of FIG. 2,however, the optical computing device 300 in FIG. 3 may be configured totransmit the electromagnetic radiation 210 through the fluid 202 via afirst sampling window 302 a and a second sampling window 302 b arrangedradially-opposite the first sampling window 302 a on the flow path 204.The first and second sampling windows 302 a,b may be similar to thesampling window 316 described above in FIG. 2 and therefore will not bedescribed again.

As the electromagnetic radiation 210 passes through the fluid 202 viathe first and second sampling windows 302 a,b, it optically interactswith the fluid 202 and optically interacted radiation 218 issubsequently directed to or otherwise received by the ICE 220 asarranged within the device 300. It is again noted that, while FIG. 3depicts the ICE 220 as receiving the optically interacted radiation 218as transmitted through the sampling windows 302 a,b, the ICE 220 mayequally be arranged at any point along the optical train of the device300, without departing from the scope of the disclosure. For example, inone or more embodiments, the ICE 220 may be arranged within the opticaltrain prior to the first sampling window 302 a and equally obtainsubstantially the same results. In yet other embodiments, the ICE 220may generate the modified electromagnetic radiation 222 throughreflection, instead of transmission therethrough. Moreover, as with thedevice 200 of FIG. 2, embodiments are contemplated herein which includethe use of at least two ICE components in the device 300 configured tocooperatively determine the characteristic of interest in the fluid 202.

The modified electromagnetic radiation 222 generated by the ICE 220 issubsequently conveyed to the detector 224 for quantification of thesignal and generation of the output signal 226 which corresponds to theparticular characteristic of interest in the fluid 202. The device 300may also include the second detector 228 for detecting radiatingdeviations stemming from the electromagnetic radiation source 208. Asillustrated, the second detector 228 may be configured to receive aportion of the optically interacted radiation 218 via the beamsplitter232 in order to detect the radiating deviations. The output signal 226and the compensating signal 230 may then be conveyed to or otherwisereceived by the signal processor 234 which may computationally combinethe two signals 230, 226 and provide in real-time or near real-time theresulting output signal 236 corresponding to the concentration of thecharacteristic of interest in the fluid 202.

Those skilled in the art will readily appreciate the various andnumerous applications that the optical computing devices 200, 300, andvarious alternative configurations thereof, may be suitably used with.For example, referring now to FIG. 4, illustrated is an exemplarywellbore drilling assembly 400 that may employ one or more of theoptical computing devices described herein in order to monitor adrilling or clean-up fluid, according to one or more embodiments. Thedrilling assembly 400 may include a drilling platform 402 that supportsa derrick 404 having a traveling block 406 for raising and lowering adrill string 408. A kelly 410 supports the drill string 408 as it islowered through a rotary table 412. A drill bit 414 is attached to thedistal end of the drill string 408 and is driven either by a downholemotor and/or via rotation of the drill string 408 from the well surface.As the bit 414 rotates, it creates a borehole 416 that penetratesvarious subterranean formations 418.

A pump 420 (e.g., a mud pump) circulates drilling fluid 422 through afeed pipe 424 and to the kelly 410, which conveys the drilling fluid 422downhole through an interior conduit defined in the drill string 408 andthrough one or more orifices in the drill bit 414. The drilling fluid422 is then circulated back to the surface via an annulus 426 definedbetween the drill string 408 and the walls of the borehole 416. Thedrilling fluid 422 serves several purposes, such as providinghydrostatic pressure to prevent formation fluids from entering into theborehole 416 and keeping the drill bit 414 cool and clean duringdrilling. The drilling fluid 422 also serves to carry drill cuttings andsolids out of the borehole 416 and suspend the drill cuttings and solidswhile drilling is paused and/or when the drill bit 414 is brought in andout of the borehole 416.

At the surface, the recirculated or spent drilling fluid 422 exits theannulus 426 and may be conveyed to one or more solids control equipment428 via an interconnecting flow line 430. In operation, the solidscontrol equipment 428 may be configured to substantially remove thedrill cuttings and solids from the drilling fluid 422 and deposit a“cleaned” drilling fluid 422 into a nearby retention pit 432 (i.e., amud pit).

Several additives or components may be added to the drilling fluid 422in order to maintain the drilling fluid 422 in proper working order andotherwise enhance drilling capabilities. In some embodiments, theadditives and components may be added to the drilling fluid 422 via amixing hopper 434 coupled to or otherwise in communication with theretention pit 432. In other embodiments, however, the additives andcomponents may be added to the drilling fluid at any other location inthe drilling assembly 400. In at least one embodiment, for example,there could be more than one retention pit 432, such as multipleretention pits 432 in series. Exemplary components that may be added tothe drilling fluid 422 include, but are not limited to, emulsions,weighting materials, viscosifiers, thickeners, rheology modifiers,thinners, deflocculants, anionic polyelectrolytes (e.g., acrylates,polyphosphates, lignosulfonates, tannic acid derivates, etc.), high-heatpolymers, clay stabilizers, clay inhibitors, tar treatments, water andother base fluids, combinations thereof, and the like. Exemplaryweighting materials may include, but are not limited to, barium sulfate(i.e., BaSO₄ or barite), hematite, ilmenite, manganese tetraoxide,galena, calcium carbonate, or the like. Exemplary thickeners and/orrheology modifiers include, but are not limited to, xanthan gum, guargum, glycol, carboxymethylcellulose, polyanionic cellulose (PAC),starch, or the like. Generally, exemplary components that may be addedto the drilling fluid 422 will include any fluid additive, material, orcomponent that is added to the drilling fluid 422 to change or maintainany preferred characteristic of the drilling fluid 422.

During drilling operations, and once critical concentrations of additivecomponents have been established in the drilling fluid 422, suchcomponents may be continuously consumed or depleted from the drillingfluid 422 due primarily to being absorbed by generated drill solids. Forexample, components, such as emulsifiers, are commonly adsorbed onto thesurfaces of drill solids which primarily include various reactive clays,such as smectite, illite, and kaolinite. As the emulsifier component isprogressively depleted from the drilling fluid 422 due to losses ondrill cuttings and solids, the stability of the drilling fluid 422emulsion may be dramatically impacted. As the drilling fluid 422emulsion becomes unstable, the rheology of the drilling fluid degrades.In extreme cases, the brine phase of the invert emulsion component canthen cause water wetting of drill solids that may adversely impactdrilling operations.

Component depletion may also result in higher viscosities of thedrilling fluid 422, thereby requiring the pump 420 to work harder andpotentially resulting in borehole 416 pressure management problems.Component depletion may also increase torque and drag on both the drillstring 408 and the drill bit 414, which could lead to a stuck pipewithin the borehole 416. Component depletion may further adverselyaffect the performance of the solids control equipment 428, such asthrough increased binding of solids in shaker screens. Additionally,component depletion may result in the accretion of solids onto metalsurfaces, barite sag events, and the adverse exchange of ions with thesurrounding formation 418.

The drilling fluid 422 may be maintained in proper working order if thedepletion rate of the components is counteracted with proper fluidtreatment or management. Accordingly, knowing the proper and correcttreatment rate in real time may be useful in optimizing the drillingfluid 422. To accomplish this, one or more optical computing devices 436(shown as optical computing devices 436 a, 436 b, 436 c, and 436 d) maybe included in the drilling assembly 400 in order to monitor thedrilling fluid 422 and/or one or more components present within thedrilling fluid 422 at one or more monitoring locations. The opticalcomputing devices 436 a-d may be substantially similar to one or both ofthe optical computing devices 200, 300 of FIGS. 2 and 3, respectively,and therefore will not be described again in detail. In exemplaryoperation, the optical computing devices 436 may measure and report thereal time characteristics of the drilling fluid 422, which may providean operator with real time data useful in adjusting various drillingparameters in order to optimize drilling operations.

In some embodiments, for example, a first optical computing device 436 amay be arranged to monitor the drilling fluid 422 as it is recirculatedor otherwise exits out of the borehole 416. As illustrated, the firstoptical computing device 436 a may be arranged on or otherwise coupledto the flow line 430, thereby being able to monitor the drilling fluid422 once it exits the annulus 426. If initial concentrations or amountsof components were known prior to conveying the drilling fluid 422 intothe borehole 416, the first optical computing device 436 a may be usefulin providing real time data indicative of how much component depletionthe drilling fluid 422 underwent after being circulated through theborehole 416.

In other embodiments, a second optical computing device 436 b may bearranged on or otherwise in optical communication with the retention pit432. The second optical computing device 436 b may be configured tomonitor the drilling fluid 422 after it has undergone one or moretreatments in the solids control equipment 428, thereby providing a realtime concentration of components remaining in the drilling fluid 422. Insome embodiments, the second optical computing device 436 b may also beconfigured to monitor the drilling fluid 422 in the retention pit 432 asadditional additive components are being added or otherwise mixed intothe drilling fluid 422 via the mixing hopper 434. For instance, thesecond optical computing device 436 b may be able to report to anoperator when a predetermined amount or proper level of a particularadditive component has been added to the drilling fluid 422 such thatthe performance of the drilling fluid 422 would be optimized. As will beappreciated, such real time measurement avoids unnecessarilyovertreating the drilling fluid 422, thereby saving time and costs.

In yet other embodiments, a third optical computing device 436 c may bearranged in the drilling assembly 400 following the retention pit 432,but prior to the mud pump 420. Alternatively, or in addition thereto, afourth optical computing device 436 d may be arranged in the drillingassembly 400 following the mud pump 420, such as being arranged at somepoint along the feed pipe 424. The third and/or fourth optical computingdevices 436 c,d may be useful in confirming whether adequate amounts orconcentrations of components have been added to the drilling fluid 422and otherwise determine whether the drilling fluid 422 is at optimal orpredetermined levels for adequate drilling operations. In otherembodiments, the third and/or fourth optical computing devices 436 c,dmay be useful in providing an initial reading of characteristics of thedrilling fluid 422, including concentrations of any components foundtherein, prior to the drilling fluid 422 being conveyed into theborehole 416. Such an initial reading may be compared with the resultingsignal provided by the first optical computing device 436 a such that adetermination of how much of a particular component remains in thedrilling fluid 422 after circulation through the borehole 416, asbriefly mentioned above.

In one or more embodiments, one or more of the optical computing devices436 a-d may be communicably coupled to a signal processor 438 andconfigured to convey a corresponding output signal 440 a-d to the signalprocessor 438. The signal processor 438 may be similar to the signalprocessor 226 of FIGS. 2 and 3, and therefore will not be describedagain in detail. The signal processor 438 may employ an algorithmconfigured to calculate or otherwise determine any differences betweenany two or more of the output signals 440 a-d. For example, the firstoutput signal 440 a may be indicative of a concentration of a componentin the drilling fluid 422 or other characteristic of the fluid 422 atthe location of the first optical computing device 436 a, the secondoutput signal 440 b may be indicative of the concentration of thecomponent or other characteristic of the fluid 422 at the location ofthe second optical computing device 436 b, and so on. Accordingly, thesignal processor 438 may be configured to determine how theconcentration of the component and/or the magnitude of thecharacteristic of interest in the fluid 422 has changed between eachmonitoring location.

In real-time or near real-time, the signal processor 438 may beconfigured to provide a resulting output signal 442 corresponding to oneor more characteristics of the fluid. In some embodiments, the resultingoutput signal 442 may provide a measured difference in the componentand/or the magnitude of the characteristic of interest in the fluid 422.In some embodiments, the resulting output signal 442 may be conveyed,either wired or wirelessly, to an operator for consideration. In otherembodiments, the resulting output signal 442 may be recognized by thesignal processor 438 as being within or without a predetermined orpreprogrammed range of suitable operation for the drilling fluid 422. Ifthe resulting output signal 442 exceeds the predetermined orpreprogrammed range of operation, the signal processor 438 may beconfigured to alert the operator so appropriate corrective action may betaken on the drilling fluid 422. Otherwise, the signal processor 438 maybe configured to autonomously undertake the appropriate correctiveaction such that the resulting output signal 442 returns to a valuewithin the predetermined or preprogrammed range of suitable operation.At least one corrective action that may be undertaken may include addingadditional components to the drilling fluid 422 via, for example, themixing hopper 434.

Still referring to FIG. 4, in other embodiments, one or more of theoptical computing devices 436 a-d may be configured to help optimizeoperating parameters for the solids control equipment 428. The solidscontrol equipment 428 may include, but is not limited to, one or more ofa shaker (e.g., shale shaker), a centrifuge, a hydrocyclone, aseparator, a desilter, a desander, combinations thereof, and the like.In other embodiments, the solids control equipment 428 may furtherinclude one or more separators operating with magnetic fields orelectric fields, without departing from the scope of the disclosure. Asbriefly mentioned above, the solids control equipment 428 may beconfigured to substantially remove the drill cuttings and other unwantedsolid particulates from the drilling fluid 422, thereby depositing a“cleaned” or substantially cleaned drilling fluid 422 into the retentionpit 432.

A common problem encountered with typical solids control equipment 428is the inefficient removal of solids and other particulates. Forexample, when solids control equipment 428 are not properly tuned, theycan sometimes pass unwanted solids or other contaminating particulatesinto the retention pit 432, thereby providing a less effective drillingfluid 422 to be recirculated back into the borehole 416. In other cases,un-tuned solids control equipment 428 may inadvertently remove valuableadditive components or materials from the drilling fluid 422, likewisehaving an adverse effect on the performance of the drilling fluid 422.

To help avoid this problem, the first and second optical computingdevices 436 a,b may be configured to monitor the inlet and outlet of thesolids control equipment 428, respectively, thereby providing anoperator with a real time indication of the efficiency of the solidscontrol equipment 428. Specifically, the first optical computing device436 a may be configured to monitor the drilling fluid 422 before orwhile it is introduced into the solids control equipment 428, and thesecond optical computing device 436 b may be configured to monitor thedrilling fluid 422 after it has undergone one or more processes ortreatments in the solids control equipment 428 or otherwise as it isbeing discharged therefrom.

The output signals 440 a,b derived from each optical computing device436 a,b, respectively, may provide the operator with valuable dataregarding the chemical and physical conditions of the drilling fluid 422before and after the solids control equipment 428. For instance, in someembodiments, the second output signal 440 b may provide the operatorwith one or more characteristics of the drilling fluid 422 as it exitsthe solids control equipment 428. As such, the second output signal 440b may verify that particular components of interest are present withinthe drilling fluid 422 and thereby serve as a quality control measurefor the drilling fluid 422. When concentrations of one or morecomponents are not at their ideal levels, adjustments to the contents ofthe drilling fluid 422 may be undertaken in response.

In some embodiments, the output signals 440 a,b may be conveyed to thesignal processor 438 and a resulting output signal 442 from the signalprocessor 438 may provide the operator with a qualitative and/orquantitative comparison of the first and second output signals 440 a,b,thereby providing valuable information as to the effectiveness of thesolids control equipment 428. For instance, depending on the resultingconcentrations of various additive components or other substancesreported by the second optical computing device 436 b, a determinationmay be made that the solids control equipment 428 is either operatingefficiently or inefficiently. Upon being notified of ineffective orinefficient performance on the part of the solids control equipment 428,the operator may then remedy the inefficiency by altering one or moreoperating parameters of the solids control equipment 428. Parameters ofthe solids control equipment 428 that may be adjusted may include, butare not limited to, adjusting a bowl speed for a centrifuge, increasingor decreasing the screen size for a shaker, increasing or decreasingg-forces in a centrifuge or hydrocyclone, adjusting a strength of amagnetic or electrical field, etc.

Fine tuning the solids control equipment 428 will ensure that thedrilling fluids 422 are maintained at proper and efficient operatinglevels. Moreover, when proper solids control practices are utilized, thecost to maintain the drilling fluid 422 and related equipment maydecrease greatly. In some embodiments, an automated control system (notshown) may be communicably coupled to both the signal processor 438 andthe solids control equipment 428. When the resulting output signal 442(or one of the output signals 440 a,b) surpasses a predeterminedthreshold for suitable drilling fluid 422, the automated control systemmay be configured to autonomously adjust the one or more operatingparameters of the solids control equipment 428.

As an example, in some embodiments, the first and second opticalcomputing devices 436 a,b may be configured to monitor components and/orsubstances in the drilling fluid 422 such as solid particulates, clays(e.g., smectite, illite, kaolin, etc.), graphitized coke, and weightingmaterials (e.g., barite), which are typically removed from the drillingfluid 422 in the various solids control equipment 428. By comparing thesecond output signal 440 b with the first output signal 440 a, it may bedetermined as to whether the solids control equipment 428 is adequatelyremoving the components and/or substances of interest, or whether it maybe beneficial to adjust one or more parameters of the solids controlequipment 428.

As another example, the first and second optical computing devices 436a,b may be configured to monitor or analyze reactive lost circulationmaterials (LCM) within the drilling fluid 422. As generally known in theart, LCM is solid material often added to the drilling fluid 422 toreduce and eventually prevent the flow of drilling fluid 422 into a weakor fractured downhole formation. Examples of LCM include, but are notlimited to, ground peanut shells, mica, cellophane, walnut shells,calcium carbonate, plant fibers, cottonseed hulls, ground rubber, andpolymeric materials. LCM is often removed from the drilling fluid 422with the solids control equipment 428. In other embodiments, however,the solids control equipment 428 may be configured to pass a certainpercentage of LCM to be recirculated back into the borehole 416. Bycomparing the second output signal 440 b with the first output signal440 a, it may be determined as to whether the solids control equipment428 is adequately removing the LCM from the drilling fluid 422 whendesired, or whether the solids control equipment 428 is adequatelyallowing an appropriate amount of LCM to pass into the retention pit 432along with the cleaned drilling fluid 422. In order to achieve optimaloperation, one or more parameters of the solids control equipment 428may be adjusted. This may also prove advantageous in providing anestimate as to how much LCM may need to be put back into the drillingfluid 422 via, for example, the mixing hopper 434 or at other locationin the drilling assembly 400, as briefly mentioned above.

In some embodiments, individual optical computing devices (not shown)may be placed at the inlet and/or outlet of each of the devices used inthe solids control equipment 428. For example, if applicable to theparticular application, one or more optical computing devices may beplaced at the inlet and/or outlet of each shaker, centrifuge,hydrocyclone, separator, desilter, and/or desander used in the solidscontrol equipment 428. As a result, the operator may be provided withdata as to the efficiency of each individual component device of thesolids control equipment 428, thereby allowing for the strategicfine-tuning of each individual piece of equipment or at least theindividual equipment responsible for the reported inefficiencies.

Still referring to FIG. 4, in yet other embodiments, one or more opticalcomputing devices, as generally described herein, may be configured orotherwise arranged to monitor wellbore servicing fluids 444 and optimizeassociated servicing fluid reclamation equipment 446. The wellboreservicing fluid 444 may be any wellbore clean-up or completion fluidknown to those skilled in the art. In some embodiments, for example, thewellbore servicing fluid 444 may be water, such as a brine or the like,or one or more spacer fluids known to those skilled in the art. Thewellbore servicing fluid 444 may be, but is not limited to, municipaltreated or fresh water, sea water, salt water (e.g., water containingone or more salts dissolved therein) naturally-occurring brine, achloride-based, bromide-based, or formate-based brine containingmonovalent and/or polyvalent cations, aqueous solutions, non-aqueoussolutions, base oils, or combinations thereof. Examples ofchloride-based brines include sodium chloride and calcium chloride.Examples of bromide-based brines include sodium bromide, calciumbromide, and zinc bromide. Examples of formate-based brines includesodium formate, potassium formate, and cesium formate.

Briefly, once drilling of the borehole 416 has been initiated, thewellbore servicing fluid 444 may be conveyed or otherwise introducedinto the borehole 416 at predetermined times in order to, among otherthings, clean up the borehole 416 and remove wellbore filter cake. Asknown in the art, wellbore filter cake is a thin, slick material thatcan build up on the walls of the borehole 416 and serves to facilitateefficient drilling operations while simultaneously helping to preventloss of the drilling fluid 422 into the subterranean formation 418 via“thief zones.” The filter cake often includes an inorganic portion(e.g., calcium carbonate) and an organic portion (e.g., starch andxanthan). Since the filter cake essentially forms a seal on the walls ofthe borehole 416, hydrocarbon production from the surrounding formation418 is substantially prevented until the filter cake is removed.

In exemplary operation, the wellbore servicing fluid 444 may becirculated through the borehole 416 in order to flush the drilling fluid422 and associated particulate matter out of the borehole 416, whilesimultaneously reacting with and removing the filter cake built up onthe walls of the borehole 416. In some embodiments, plugs of thewellbore servicing fluid 444 may separate individual plugs of thedrilling fluid 422. In other embodiments, however, the wellboreservicing fluid 444 may be circulated through the borehole 416 at theconclusion of a drilling operation in order to perform remedialtreatments in preparation for hydrocarbon production. As the wellboreservicing fluid 444 contacts the filter cake built up in the borehole416, in some embodiments, a chemical reaction ensues and the filter cakeis gradually dissolved and circulated out of the borehole 416 witheither the wellbore servicing fluid 444 or the drilling fluid 422. Inother embodiments, the filter cake may be solubilized, dissolved orotherwise eroded from the borehole 416.

In some embodiments, the first optical computing device 436 a may beconfigured to monitor the drilling fluid 422 or the wellbore servicingfluid 444 as it exits the borehole 416 via the interconnecting flow line430 and determine a concentration of a characteristic thereof, such as achemical constituent or compound corresponding to the filter cake thatmay be present therein. For instance, the first optical computing device436 a may be configured to monitor the drilling fluid 422 and/or thewellbore servicing fluid 444 for concentrations of calcium carbonate,barite, clays, entrapped components, or the like.

In at least one embodiment, the output signal 440 a from the firstoptical computing device 436 a may be compared with the output signal440 d from the fourth optical computing device 436 d, for example, todetermine how much filter cake chemical constituent/compound was removedfrom the borehole 416. As the contact time with the wellbore servicingfluid 444 increases, the concentration of the filter cake chemicalconstituent/compound will at first increase and then gradually decreaseas the filter cake is progressively reacted and/or dissolved and removedfrom the borehole 416. The output signal 440 a from the first opticalcomputing device 436 a may provide the operator with a real timeindication of how much filter cake is being dissolved or otherwiseremoved from the borehole 416. As a result, the operator is informed inreal time as to whether the borehole 416 cleanup operation is/wassuccessful.

In some embodiments, upon returning to the surface and exiting theborehole 416, the wellbore servicing fluid 444 may be conveyed to one ormore servicing fluid reclamation equipment 446 fluidly coupled to theannulus 426. The reclamation equipment 446 may be configured to receiveand rehabilitate the wellbore servicing fluid 444 in preparation for itsreintroduction into the borehole 416, if desired. The reclamationequipment 446 may include one or more filters or separation devicesconfigured to clean the wellbore servicing fluid 444. In at least oneembodiment, the reclamation equipment 446 may include a diatomaceousearth filter, or the like.

In some embodiments, the drilling assembly 400 may further include afifth optical computing device 436 e and a sixth optical computingdevice 436 f used in conjunction with the reclamation equipment 446. Thefifth and sixth optical computing devices 436 e,f may be substantiallysimilar to one or both of the optical computing devices 200, 300 ofFIGS. 2 and 3, respectively, and therefore will not be described againin detail. As illustrated, the fifth and sixth optical computing devices436 e,f my be used to monitor an inlet and an outlet of the reclamationequipment 446, respectively, thereby providing the operator with a realtime determination of one or more characteristics of the wellboreservicing fluid 444 before and after being treated in the reclamationequipment 446. In some embodiments, for example, the characteristic ofthe wellbore servicing fluid 444 may include a concentration of achemical constituent or compound corresponding to the filter cake (e.g.,calcium carbonate) before and after treatment in the reclamationequipment 446. In other embodiments, the characteristic of the wellboreservicing fluid 444 may correspond to a density of the wellboreservicing fluid 444 before and after treatment in the reclamationequipment 446. In yet other embodiments, the characteristic of thewellbore servicing fluid 444 may correspond to the turbidity of thefluid 444 before and after treatment in the reclamation equipment 446.

The output signals 440 e and 440 f derived from each optical computingdevice 436 e,f, respectively, may be conveyed to the signal processor438 for processing. In some embodiments, the sixth output signal 440 fmay provide the operator with one or more characteristics of thewellbore servicing fluid 444 as it exits the reclamation equipment 446.As such, the sixth output signal 440 f may serve as a quality controlmeasure for the wellbore servicing fluid 444, and provide an indicationto the operator whether the wellbore servicing fluid 444 is adequatelyrehabilitated before it is reintroduced into the borehole 416.

In some embodiments, the resulting output signal 442 from the signalprocessor 438 may be indicative of a difference between the fifth andsixth output signals 440 e,f, thereby providing valuable information asto the effectiveness of the reclamation equipment 446 in rehabilitatingthe wellbore servicing fluid 444. For instance, depending on theresulting concentrations of the characteristic reported by the sixthoptical computing device 436 f, a determination may be made that thereclamation equipment 446 is either operating efficiently orinefficiently, and proper adjustments to the reclamation equipment 446may be made in response thereto, if needed. As a result, optimaloperating parameters for the reclamation equipment 446 may be achieved.In some embodiments, an automated control system may be communicablycoupled to both the signal processor 438 and the reclamation equipment446, and the automated control system may be configured to autonomouslyadjust the reclamation equipment 446 when the resulting output signal442 (or one of the fifth and sixth output signals 440 e,f) surpasses apredetermined threshold.

Still referring to FIG. 4, in other embodiments, one or more opticalcomputing devices, as generally described herein, may be configured tomonitor the drilling fluid 422 at one or more points in the drillingassembly 400 for the formation and/or concentration of gas hydrates. Asgenerally known in the art, gas hydrates are clathrates or crystallineinclusion compounds of gas molecules in water which can form undercertain temperature and pressure conditions (e.g., low temperature andhigh pressure) during drilling operations. Since gas hydrates consist ofmore than 85% water, their formation could remove significant amounts ofwater from the drilling fluid 422, thereby changing the fluid propertiesof the drilling fluid 422. This could result in salt precipitation or anincrease in fluid weight.

Agglomeration of these gas hydrates in the drilling fluid 422 (orproduction tubing), or the formation of a solid hydrate plug, canpotentially cause hazardous flow assurance problems. For instance, gashydrates could form in the drill string 408 and associated drillingequipment, a blow-out preventer (BOP) stack (not shown), choke and killlines (not shown), etc., which could result flow blockage, hindrance todrill string 408 movement, loss of circulation, and even abandonment ofthe well.

In at least one embodiment, the drilling assembly 400 may furtherinclude a seventh optical computing device 436 g arranged downhole inthe borehole 416 and configured to monitor the drilling fluid 422 withinthe annulus 426 for the presence of gas hydrates. The seventh opticalcomputing device 436 g may be substantially similar to one or both ofthe optical computing devices 200, 300 of FIGS. 2 and 3, respectively,and therefore will not be described again in detail. In particular, theseventh optical computing device 436 g may include at least oneintegrated computational element (not shown) configured to detect one ormore types of gas hydrates, such as methane clathrates or methanehydrates.

It should be noted that while the seventh optical computing device 436 gis illustrated as a single optical computing device, it is contemplatedherein to include any number of optical computing devices arrangedwithin the borehole 416 to monitor the drilling fluid 422 for gashydrate formation. Moreover, while the seventh optical computing device436 g is shown as being coupled at or near the drill bit 414, thoseskilled in the art will readily appreciate that the seventh opticalcomputing device 436 g, and any number of other optical computingdevices, may be arranged at any point along the drill string 408,without departing from the scope of the disclosure.

An output signal 440 g from the seventh optical computing device 436 gmay be indicative of a characteristic of the drilling fluid 422, such asthe concentration of one or more gas hydrates within the drilling fluid422. In some embodiments, the output signal 440 g may be sent to theoperator, either wired or wirelessly, and provide the operator with realtime qualitative and/or quantitative data regarding the concentration ofgas hydrates within the drilling fluid 422 at that particular location.In other embodiments, the output signal 440 g may be conveyed to thesignal processor 438 for further processing in view of or in conjunctionwith one or more of the other output signals 440 a-f.

When the concentration of gas hydrates in the drilling fluid 422surpasses or otherwise reaches a predetermined threshold limit, asdetected or reported by the seventh optical computing device 436 g, analert or warning may be provided to the operator such that one or morecorrective actions may be undertaken. Corrective actions may includeadding treatment substances or compounds to the drilling fluid in orderto counteract the formation of additional gas hydrates and otherwisereduce the concentration of gas hydrates within the drilling fluid 422.In other embodiments, a corrective action could include changing thesalinity level of the drilling fluid.

In some embodiments, for example, a gas hydrate inhibitor may be addedto the drilling fluid 422. Gas hydrate inhibitors shift thethermodynamic limit of gas hydrate formation to lower temperatures andhigher pressures (i.e., thermodynamic inhibition), thereby decreasingthe tendency of gas hydrate formation. Exemplary gas hydrate inhibitorsinclude, but are not limited to salts (e.g., sodium chloride), methanol,alcohols, glycol, diethylene glycol, glycerol, polyglycerol,combinations thereof, and the like. In some embodiments, combinations ofsalts with water-soluble organic compounds may be used as the gashydrate inhibitor. In other embodiments, partially-hydrolyzedpolyacrylamide (PHPA) may be used as a gas hydrate inhibitor and used tolinks particles together to improve rheology without increased colloidalsolids loading.

In some embodiments, the gas hydrate inhibitor may be added to thedrilling fluid 422 via the mixing hopper 434 or at any other point inthe drilling assembly 400. Following the influx of the gas hydrateinhibitor into the borehole 416, the seventh output signal 440 g of theseventh optical computing device 436 g may then provide the operatorwith the real time concentration of gas hydrates within the drillingfluid 422. If the concentration of gas hydrates fails to decrease,additional gas hydrate inhibitor may be added to the drilling fluid 422as needed. Otherwise, if the concentration of gas hydrates returns to amanageable or “safe” operating level, the seventh output signal 440 gmay inform the operator that the influx of additional gas hydrateinhibitor may be maintained, reduced, or eliminated altogether. As willbe appreciated, such a process of managing the addition of gas hydrateinhibitor (or any other treatment substance) to the drilling fluid 422may be fully automated using an automated control system, as generallydescribed above.

Accordingly, the seventh optical computing device 436 g may provide anindication of whether the gas hydrate inhibitor (or any other treatmentsubstance, for that matter) is effective or not in its intended purpose.The effectiveness of the gas hydrate inhibitor may also be determinedusing a before-and-after comparison of the concentration of the gashydrate inhibitor within the drilling fluid 422. For instance, the thirdand/or fourth optical computing devices 436 c,d may provide an initialreading of the concentration of gas hydrate inhibitor in the drillingfluid 422 prior to the drilling fluid 422 being conveyed into theborehole 416. The first optical computing device 436 a may provide theconcentration of the gas hydrate inhibitor after having been circulatedthrough the borehole 416. The respective output signals output signals440 c,d and 440 a may be processed in the signal processor 438, therebyproviding the operator with a real time difference between the twosignals, which may be indicative as to whether the gas hydrate inhibitoris properly functioning.

Those skilled in the art will readily recognize that, in one or moreembodiments, electromagnetic radiation may be derived from the fluidbeing analyzed itself, such as the drilling fluid 422, and otherwisederived independent of any electromagnetic radiation source 208 (FIGS. 2and 3). For example, various substances naturally radiateelectromagnetic radiation that is able to optically interact with theICE 220 (FIGS. 2 and 3). In some embodiments, for example, the fluidbeing analyzed may be a blackbody radiating substance configured toradiate heat that may optically interact with the ICE 220. In otherembodiments, the fluid may be radioactive or chemo-luminescent and,therefore, radiate electromagnetic radiation that is able to opticallyinteract with the ICE 220. In yet other embodiments, the electromagneticradiation may be induced from the fluid by being acted uponmechanically, magnetically, electrically, combinations thereof, or thelike. For instance, in at least one embodiment, a voltage may be placedacross the fluid in order to induce the electromagnetic radiation. As aresult, embodiments are contemplated herein where the electromagneticradiation source 208 is omitted from the optical computing devicesdescribed herein.

It is recognized that the various embodiments herein directed tocomputer control and artificial neural networks, including variousblocks, modules, elements, components, methods, and algorithms, can beimplemented using computer hardware, software, combinations thereof, andthe like. To illustrate this interchangeability of hardware andsoftware, various illustrative blocks, modules, elements, components,methods and algorithms have been described generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware will depend upon the particular application and any imposeddesign constraints. For at least this reason, it is to be recognizedthat one of ordinary skill in the art can implement the describedfunctionality in a variety of ways for a particular application.Further, various components and blocks can be arranged in a differentorder or partitioned differently, for example, without departing fromthe scope of the embodiments expressly described.

Computer hardware used to implement the various illustrative blocks,modules, elements, components, methods, and algorithms described hereincan include a processor configured to execute one or more sequences ofinstructions, programming stances, or code stored on a non-transitory,computer-readable medium. The processor can be, for example, a generalpurpose microprocessor, a microcontroller, a digital signal processor,an application specific integrated circuit, a field programmable gatearray, a programmable logic device, a controller, a state machine, agated logic, discrete hardware components, an artificial neural network,or any like suitable entity that can perform calculations or othermanipulations of data. In some embodiments, computer hardware canfurther include elements such as, for example, a memory (e.g., randomaccess memory (RAM), flash memory, read only memory (ROM), programmableread only memory (PROM), erasable read only memory (EPROM)), registers,hard disks, removable disks, CD-ROMS, DVDs, or any other like suitablestorage device or medium.

Executable sequences described herein can be implemented with one ormore sequences of code contained in a memory. In some embodiments, suchcode can be read into the memory from another machine-readable medium.Execution of the sequences of instructions contained in the memory cancause a processor to perform the process steps described herein. One ormore processors in a multi-processing arrangement can also be employedto execute instruction sequences in the memory. In addition, hard-wiredcircuitry can be used in place of or in combination with softwareinstructions to implement various embodiments described herein. Thus,the present embodiments are not limited to any specific combination ofhardware and/or software.

As used herein, a machine-readable medium will refer to any medium thatdirectly or indirectly provides instructions to a processor forexecution. A machine-readable medium can take on many forms including,for example, non-volatile media, volatile media, and transmission media.Non-volatile media can include, for example, optical and magnetic disks.Volatile media can include, for example, dynamic memory. Transmissionmedia can include, for example, coaxial cables, wire, fiber optics, andwires that form a bus. Common forms of machine-readable media caninclude, for example, floppy disks, flexible disks, hard disks, magnetictapes, other like magnetic media, CD-ROMs, DVDs, other like opticalmedia, punch cards, paper tapes and like physical media with patternedholes, RAM, ROM, PROM, EPROM and flash EPROM.

It should also be noted that the various drawings provided herein arenot necessarily drawn to scale nor are they, strictly speaking, depictedas optically correct as understood by those skilled in optics. Instead,the drawings are merely illustrative in nature and used generally hereinin order to supplement understanding of the systems and methods providedherein. Indeed, while the drawings may not be optically accurate, theconceptual interpretations depicted therein accurately reflect theexemplary nature of the various embodiments disclosed.

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered,combined, or modified and all such variations are considered within thescope and spirit of the present invention. The invention illustrativelydisclosed herein suitably may be practiced in the absence of any elementthat is not specifically disclosed herein and/or any optional elementdisclosed herein. While compositions and methods are described in termsof “comprising,” “containing,” or “including” various components orsteps, the compositions and methods can also “consist essentially of” or“consist of” the various components and steps. All numbers and rangesdisclosed above may vary by some amount. Whenever a numerical range witha lower limit and an upper limit is disclosed, any number and anyincluded range falling within the range is specifically disclosed. Inparticular, every range of values (of the form, “from about a to aboutb,” or, equivalently, “from approximately a to b,” or, equivalently,“from approximately a-b”) disclosed herein is to be understood to setforth every number and range encompassed within the broader range ofvalues. Also, the terms in the claims have their plain, ordinary meaningunless otherwise explicitly and clearly defined by the patentee.Moreover, the indefinite articles “a” or “an,” as used in the claims,are defined herein to mean one or more than one of the element that itintroduces. If there is any conflict in the usages of a word or term inthis specification and one or more patent or other documents that may beincorporated herein by reference, the definitions that are consistentwith this specification should be adopted.

The invention claimed is:
 1. A system, comprising: solids controlequipment fluidly coupled to a borehole and configured to receivedrilling fluid from the borehole, the solids control equipment having aninlet and an outlet; a first optical computing device arranged adjacentthe inlet and having a first integrated computational element configuredto optically interact with the drilling fluid as it enters the solidscontrol equipment and thereby generate a first output signalcorresponding to a first measurement of a characteristic of the drillingfluid; a second optical computing device arranged adjacent the outletand having a second integrated computational element configured tooptically interact with the drilling fluid as it exits the solidscontrol equipment and thereby generate a second output signalcorresponding to a second measurement of the characteristic of thedrilling fluid; and a signal processor communicably coupled to the firstand second optical computing devices and configured to receive the firstand second output signals and provide a resulting output signal, thesignal processor further configured to normalize one of the first orsecond output signals with a compensating signal indicative of anintensity deviation of an electromagnetic radiation used for opticallyinteracting at least one of the first or second integrated computationalelements with the drilling fluid.
 2. The system of claim 1, wherein thesolids control equipment is at least one of a shaker, a centrifuge, ahydrocyclone, a separator, a desilter, a desander, and a separator thatoperates using magnetic or electrical fields.
 3. The system of claim 1,wherein the resulting output signal is indicative of how thecharacteristic of the drilling fluid changes between the inlet andoutlet.
 4. The system of claim 1, wherein the characteristic of thedrilling fluid is a concentration of a substance in the drilling fluid.5. The system of claim 4, wherein the substance comprises a substanceselected from the group consisting of solid particulates, clays,weighting materials, and lost circulation materials.
 6. The system ofclaim 1, further comprising an automated control system communicablycoupled to the signal processor and configured to adjust one or moreoperating parameters of the solids control equipment in response to theresulting output signal.
 7. The system of claim 1, further comprising: afirst detector configured to receive the optically interacted light fromthe first integrated computational element and generate the first outputsignal; and a second detector configured to receive the opticallyinteracted light from the second integrated computational element andgenerate the second output signal.
 8. The system of claim 1, furthercomprising: a first electromagnetic radiation source arranged in thefirst optical computing device and being configured to emitelectromagnetic radiation that optically interacts with the drillingfluid prior to entering the solids control equipment; and a secondelectromagnetic radiation source arranged in the second opticalcomputing device and being configured to emit electromagnetic radiationthat optically interacts with the drilling fluid after exiting thesolids control equipment.
 9. A method of determining a characteristic ofa drilling fluid, comprising: conveying the drilling fluid to solidscontrol equipment fluidly coupled to a borehole, the solids controlequipment having an inlet and an outlet; generating a first outputsignal corresponding to a first measurement of the characteristic of thedrilling fluid made with a first optical computing device arrangedadjacent the inlet, the first optical computing device having a firstintegrated computational element configured to optically interact withthe drilling fluid as it enters the solids control equipment; generatinga second output signal corresponding to a second measurement of thecharacteristic of the drilling fluid made with a second opticalcomputing device arranged adjacent the outlet, the second opticalcomputing device having a second integrated computational elementconfigured to optically interact with the drilling fluid as it exits thesolids control equipment; receiving the first and second output signalswith a signal processor communicably coupled to the first and secondoptical computing devices; receiving a compensating signal from at leastone of the first or second optical computing devices, the compensatingsignal indicative of an intensity deviation of an electromagneticradiation used for optically interacting at least one of the first orsecond integrated computational elements with the drilling fluid; andgenerating a resulting output signal with the signal processor, whereinthe generating the resulting output signal comprises normalizing one ofthe first or second output signals with the compensating signal.
 10. Themethod of claim 9, wherein generating the resulting output signalcomprises determining how the characteristic of the drilling fluidchanged between the inlet and the outlet of the solids controlequipment.
 11. The method of claim 9, wherein the characteristic of thedrilling fluid is a concentration of a substance in the drilling fluid.12. The method of claim 11, wherein the substance comprises a substanceselected from the group consisting of solid particulates, clays,weighting materials, and lost circulation materials.
 13. The method ofclaim 9, further comprising conveying the resulting output signal to auser for consideration.
 14. The method of claim 9, further comprisingadjusting one or more operating parameters of the solids controlequipment in response to the resulting output signal.
 15. The method ofclaim 14, wherein the one or more operating parameters of the solidscontrol equipment are adjusted by an automated control systemcommunicably coupled to the signal processor.
 16. The method of claim 9,wherein the second output signal is a concentration of thecharacteristic of the drilling fluid as measured by the second opticalcomputing device, the method further comprising using the second outputsignal as a quality control measure for the drilling fluid.
 17. Asystem, comprising: solids control equipment fluidly coupled to aborehole and configured to receive drilling fluid from the borehole, thesolids control equipment having an inlet and an outlet; an opticalcomputing device arranged adjacent the outlet and having an integratedcomputational element configured to optically interact with the drillingfluid as it exits the solids control equipment and generate an outputsignal corresponding to a characteristic of the drilling fluid; and asignal processor communicably coupled to the optical computing deviceand configured to receive the output signal and provide a resultingoutput signal indicative of the characteristic of the drilling fluid,and further configured to normalize the output signal according to acompensating signal indicative of an intensity deviation of anelectromagnetic radiation used for optically interacting at least one ofthe first or second integrated computational elements with the drillingfluid.
 18. The system of claim 17, wherein the solids control equipmentis at least one of a shaker, a centrifuge, a hydrocyclone, a separator,a desilter, a desander, and a separator that operates using magnetic orelectrical fields.
 19. The system of claim 17, wherein thecharacteristic of the drilling fluid is a concentration of a substancein the drilling fluid as the drilling fluid exits the solids controlequipment.
 20. The system of claim 19, wherein the substance comprises asubstance selected from the group consisting of solid particulates,clays, weighting materials, and lost circulation materials.
 21. Thesystem of claim 17, wherein the resulting output signal is used as aquality control measure for the drilling fluid.